Urbanization and rising environmental risks resulting from human-centric activities threaten more species with extinction than ever. A report from the International Institute of sustainable development 2022 estimates that over 850 different vertebrates are directly threatened due to habitat loss from urban land expansion.
At the same time, cities are facing massive challenges in creating urban environments where people thrive. Population growth in cities increases the need for infrastructure in urban areas and imposes high pressure on the environment. Intergovernmental Panel on Climate Change 2022 also exacerbates the rising inequality in cities, particularly affecting the urban poor. Summarizing these challenges highlights two broad areas: 1) Providing access to essential services and resources and 2) Increasing risk exposure.
Cities are central to embracing responsibility for citizens’ well-being and the environment. Sustainable Development Goals 11 drives efforts to make cities inclusive, safe, resilient, and sustainable. It focuses on multiple goals to achieve urban sustainability: adequate housing, access to public transport, access to public spaces and parks, protection of natural and cultural heritage, climate action, and protection from disaster. In its latest World Cities Report 2022, UN-Habitat highlights that building economic, social, and environmental resilience must be at the heart of the future of cities.
Urban areas need a variety of assets called social infrastructure combined with roads and buildings. Power generation and distribution, water distribution, and waste-water management are prime pillars of cities’ infrastructure. As per UNEP 2022, infrastructure to be sustainable shall underline the following: to provide value for money; quality service; be inclusive and resilient, and foster health & well-being. Building with – rather than against nature has direct benefits for cities. Nature-based infrastructure (NBI) provides cost-effective and climate-resilient infrastructure solutions.
The Nature-Based Infrastructure solution harnesses nature to provide infrastructure service. Nature-based solutions take inspiration from forests, mangroves, wetlands, and grasslands, and the resultant can be engineered or grey structures. Apart from functioning as a basic infrastructure, it enables and supports wider goals by offering valuable co-benefits for communities and the environment.
NBI can sequester carbon, function as a habitat for endangered species, support people’s livelihood, and offer space for recreation. Let us look at the examples:
Mangrove for flood protection
Mangroves can protect communities from floods, similar to the conventional solution of building a seawall. Moreover, it provides co-benefits for biodiversity and local livelihood.
In Kigali (Rwanda), the city maximises the ecosystem by restoring wetlands, which help reduce flood risk to vulnerable communities and provide attractive green spaces for Kigali residents.
In another example, Rosario (Argentina) launched an urban food production programme utilizing flood-prone lowlands, strips along highways, and designated green belts converted into agriculture space. The programme shortened the food supply chain and reduced the flood risks by absorbing water.
Investing in Urban Green Space
Urban green space includes parks, gardens, forests, meadows, and other vegetated areas. Green space in the region helps increase surface water storage and groundwater recharge. One of the critical climate adaptation benefits is that they reduce water runoff and reduce flood risk in cities. Being permeable in nature, green space absorbs more water than built-up areas.
Green Roofs and facade
Buildings with green roofs and façades provide shade and cooling, reducing the urban heat island effect and the need for additional cooling. Green roofs improve air quality, reduce energy use, and store carbon. Many studies have concluded that installing a green roof can reduce energy consumption by 15%-45%.
Nature-based stormwater infrastructure
Unlike grey infrastructure, NBI manages water and treats it as a resource. NBI-based storm infrastructure absorbs water and increases water infiltration. By filtering stormwater and letting it infiltrate the soil, nature-based stormwater infrastructure also contributes to green water recharge. It includes bioswales, rain gardens, green roofs, wetlands, and flood plains.
Wetlands and Lakes
Wetlands and lakes are crucial for reducing the consequences of climate change. Studies have shown that wetlands can reduce nitrogen and organic concentration and is more effective than grey wastewater treatment infrastructure. It includes marshes, swamps, peatlands, and mangroves.
NBI compliment and supports the existing infrastructure of cities. It provides a supportive infrastructure to public transportation and NMT users by reducing outdoor air temperature and providing shade under intense heat which else restricts people from walking, cycling, and waiting in transit stops. It also supports water management in cities by providing clean water, allowing water to infiltrate the ground, and restoring groundwater. Moreover, also improve energy efficiency by reducing consumption.
To maximize the benefits of NBI, planners, policymakers, and city authorities can benefit from integrated implementation, and stakeholders can have a more holistic perspective on infrastructure investments.
This article is based on Report:- The Value of Incorporating Nature in Urban Infrastructure Planning.